Lag when viewing meshes in texture shading mode
Ps1 texture for world maps reached a maximum of 1024x1024 pixels and a lot of &quot;sharpening filter applied, from photoshop&quot;.
If you're using such an old computer, the maximum texture will be 1280x1280 pixels for Ps1 styles. Your texture is causing the lag, yes. Upgrade to Blender 2.79. Most of texture mip issues have been solved there as well, if you don't want to go to 2.8.